In China, the first cannon–barrel design portrayed in artwork was a stone sculpture dated to 1128 AD, found in Sichuan province, although the oldest archaeological discovery of a cannon is a bronze cannon of China inscribed with the date “2nd year of the Dade era, Yuan Dynasty” (1298 AD). The prototype to the metal barrel was of course one made of bamboo, which was recorded in use by a Chinese garrison commander at Anlu, Hubei province, in the year 1132. One of the earliest references to the destructive force of a cannon in China was made by Zhang Xian in 1341, with his verse known as The Iron Cannon Affair. Zhang wrote that its cannonball could “pierce the heart or belly when it strikes a man or horse, and can even transfix several persons at once.” Jiao Yu wrote that the cannon, called the ‘eruptor’, was cast in bronze, and had an average length of 4 ft and 5 in. He wrote that some cannons were simply filled with 100 or so lead balls, but others had large rounds that produced a bursting charge upon impact, called the ‘flying–cloud thunderclap eruptor’. He wrote of how the Chinese in his day had figured out how to pack hollow cast iron shells of cannonballs with gunpowder to create an explosive effect upon contact with enemy targets. In perspective, exploding cannonball rounds were not discovered in Europe until the 16th century.
The fire-spear developed as a functional battlefield weapon from the early twelfth to the early thirteenth century. Whatever prototype forms it had in the tenth century were not regularly weaponized and distributed to the army, nor was the knowledge of how to make them widely available, until the twelfth century. Fire-spears played no significant role in the defense of the Song capital in 1126–7, but only a few years later they played a critical role at the siege of De’an. Knowledge of this weapon, both how to make it and, just as significantly, how to use it on the battlefield, was not widespread in the early twelfth century, even at the capital. Very few people may have known the possibilities presented by gunpowder’s capabilities; ordinary soldiers might have known how to use bombs, grenades, and smoke bombs, without being aware of what the powder inside a bomb would do when ignited inside a tube with an open end. This knowledge would have spread very quickly during the intense period of warfare that began after the fall of the Song capital in 1127.
The next major improvement to the fire-spear was crucial in the development of the gun. People began to realize that the jet of flame produced by the tube of gunpowder had sufficient force to shoot small projectiles with enough energy to enhance the personnel-wounding effects of the flame. It is only because these weapons came to be used against people, rather than for attempting to batter down walls, that adding bits of metal or pottery shards to the packed gunpowder made any sense. We see here an intellectual evolution whereby gunpowder came to be understood as a propellant, as well as an incendiary mixture. By the early thirteenth century, shrapnel of various kinds was regularly added to the gunpowder of a fire-spear.
The tube of most fire-spears at that time was usually made of layers of paper or sections of bamboo, about two feet long. It was therefore not only light in weight, but also cheap. Perhaps more surprisingly, both paper and bamboo tubes were also reusable. The fire-spear could thus be easily manufactured, and its capabilities added to pre-existing spears. The major limitation of the fire-spear was not so much the range of its flame, as the duration. A fire-spear was an enhanced polearm, not a missile weapon like the bow or crossbow. This use of gunpowder as a propellant would not lead to the gun, however, because the fragile tubes were limited in the amount of pressure they could withstand, the projectiles used did not occlude the tube opening sufficiently to exploit the sudden discharge of built-up pressure, and the weapon was not conceived of as a missile arm.
While the fire-spear demonstrated the possibilities of gunpowder to carry a projectile, it was the parallel development of the fire-tube (huotong) that would lead more directly to the metal-barreled tube. The fire-tube was a bamboo tube with a handle at the base that initially operated in exactly the same manner as the fire-spear, minus the spear. This separation of the fire-tube from a functioning hand-to-hand weapon was important for two reasons: first, it emphasized the independent value of a chemical-based weapon and, second, it left the user in dire need of a hand-to-hand weapon. The latter problem was solved when an iron barrel was fixed to the handle, rendering the spent weapon a still usable club. Indeed, the first mention of an iron-barreled fire-tube emphasizes this point:
The Bandit-striking Penetrating Tube: Use iron to make a barrel three feet long with a handle two feet long. Infantry use this. In one discharge the pellet is able to strike a bandit at a distance of three hundred paces (five hundred yards). This tube can also be used to hit bandits. This one device with two uses is the most advantageous.
Needham dates this particular section of the text, the Fire Dragon Classic (Huolong Jing), to the first half of the fourteenth century, but believed that the quoted passage is ‘‘probably as old as 1200.’’ He also discounts the range of the projectile as a gross exaggeration, asserting that the flames carried only twenty or thirty feet. This would be consistent with the previous fire-tubes and fire-spears, so Needham also believes that the bandit-striking penetrating tube did not fire a single pellet, but rather a large number of them. The language is ambiguous, since either the singular or plural is possible, though the accompanying drawing seems to show a spray of particles. Analyzing the drawing is problematic, since not only is it possible that the drawings come from a different period than the text, it is also a grave mistake to ‘‘read’’ the image as if it were a photograph. The images themselves are presumably from the fourteenth century version of the text, though Needham is not explicit about this. If the weapon fired a single projectile out of an iron barrel with sufficient occlusion of the barrel and a high-enough nitrate mixture of gunpowder, then five hundred yards might well be possible as a lethal range. It would be terribly inaccurate, of course, and it would probably date more toward the middle or end of the thirteenth century, than the beginning of it.
Near-constant warfare starting in the first quarter of the twelfth century led to the development of a wide variety of fire-spears and fire-tubes in the early twelfth through the mid-thirteenth century. At some point during the thirteenth century, the true gun with a metal barrel, high-nitrate gunpowder, and firing a single projectile was invented, but this did not drive out all of the other weapons, or cause a sudden shift in military practice. Fire-spears and fire-tubes gradually shifted from specialized siege equipment or naval weapons to battlefield anti-personnel weapons. But the precursors to the true gun, and the true gun itself, were weapons born of siege and naval warfare, and then transferred to the open field. The power of first Jurchen, and then Mongol, cavalry forced the Song off the open field and into fortified cities or on to rivers to stop their advances. In time, all sides gained knowledge of these weapons, and first the Jurchen and then the Song advantage in siege and naval warfare was negated by the Mongols. Warfare would never be the same.
